Readout device, readout method, program, and program recording medium

ABSTRACT

A readout device includes a first recording medium having recorded therein data of arbitrary plural portions of a period of a predetermined length in temporally continuous content; a second recording medium having recorded therein data of the entire content; and a readout control unit that controls, when the readout of data of the content is requested, the readout of data from the first recording medium and from the second recording medium such that data of any one of the portions recorded in the first recording medium is read out and data following the data read out from the first recording medium is read out from the second recording medium.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority from Japanese Patent ApplicationNo. JP 2005-189815 filed on Jun. 29, 2005, the disclosure of which ishereby incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a readout device, a readout method, aprogram, and a program recording medium, and, more particularly to areadout device and a readout method for reading out content, a program,and a program recording medium.

2. Description of the Related Art

There is a recording and reproducing system that makes it possible toeasily handle a large quantity of contents by recording data of thecontents in plural recording media and automating mounting of therecording media in a drive.

FIG. 1 is a block diagram showing a structure of a recording andreproducing system in the past. A video/audio encoder 11 encodes,according to the Moving Pictures Experts Group (MPEG) system, image dataof a baseband corresponding to an input image signal inputted. Thevideo/audio encoder 11 encodes, according to the MPEG system, sound dataof a baseband corresponding to a sound signal inputted (not shown). Thevideo/audio encoder 11 supplies data obtained by the encoding to astream encoder 12.

The stream encoder 12 multiplexes the encoded data supplied from thevideo/audio encoder 11, converts the multiplexed data into a stream ofthe MPEG transport stream system or the MPEG program stream system, andsupplies the stream obtained by the conversion to a write buffer 13.

The write buffer 13 temporarily stores the stream (data) supplied fromthe stream encoder 12 and supplies the stream (the data) stored thereinto a drive 14.

The drive 14 records the data supplied from the write buffer 13 in anoptical disk 15 mounted therein as a file.

A juke system 16 controls mounting of the optical disk 15 in the drive14 and unmounting of the optical disk 15 from the drive 14. The jukesystem 16 causes a picker 18 to select any one of plural disks 15 fromdisk slots 17 that store the respective optical disks 15. The picker 18conveys the optical disk 15 selected and mounts the optical disk 15 inthe drive 14 under the control by the juke system 16. The picker 18 alsoconveys the optical disk 15 unmounted from the drive 14 and stores theoptical disk 15 in any one of the disk slots 17 under the control by thejuke system 16. In other words, the juke system 16 controls the picker18.

The drive 14 reads out the data recorded as the file from the opticaldisk 15 mounted therein and supplies the data read out to a read buffer19. The read buffer 19 includes a semiconductor memory or a hard diskand temporarily stores the data (a stream) supplied from the drive 14.The read buffer 19 absorbs a readout jitter, planarizes a data rate tobe fixed, and supplies the data (the stream) stored therein to a streamdecoder 20.

The stream decoder 20 separates the stream of the MPEG transport streamsystem or the MPEG program stream system into image data and sound dataand supplies the image data and the sound data separated to avideo/audio decoder 21.

The video/audio decoder 21 decodes the image data and the sound dataencoded into image data and sound data of a so-called baseband. Thevideo/audio decoder 21 supplies an output image signal and sound signal(not shown), which are based on the image data and the sound data of thebaseband obtained by the decoding, to a monitor 22. The monitor 22displays an image on the basis of the output image signal and outputssound on the basis of the sound signal supplied.

Processing of reproduction will be explained with reference to FIG. 2.When reproduction is requested from a user at time t₀, the optical disk15 having stored therein data of content requested to be reproduced isconveyed from the disk slot 17 to the drive 14 and mounted in the drive14 by the picker 18 at time t₁.

At time t₂, data recorded in the optical disk 15 mounted is started tobe read out and stored in the read buffer 19 by the drive 14. When datahaving a predetermined data amount is accumulated in the read buffer 19at time t₃, the data stored in the read buffer 19 is read out to thestream decoder 20. The video/audio decoder 21 decodes the image data andthe sound data and supplies an output image signal and sound signalcorresponding to image data and sound data obtained by the decoding tothe monitor 22. At time t₄, the monitor 22 displays an image and outputssound on the basis of the output image signal and sound signal.

From time t₀ when the reproduction is requested by the user until timet₄ when the image is displayed on the monitor 22, a time lag equivalentto time necessary for mounting the optical disk 15, which is stored inthe disk slot 17, in the drive 14 and reading out the image data fromthe optical disk 15 mounted occurs. This time lag is about twentyseconds to thirty seconds depending on a structure of the recording andreproducing system.

This time lag occurs every time reproduction is requested. Thus, theuser feels extremely heavy stress because of the time lag. This is asignificant problem in terms of operability.

In the past, there is a video recording and reproducing apparatusincluding recording and reproducing means for recording a video and/orsound signal in a first recording medium or reproducing the video orsound signal from the first recording medium, a second recording mediumthat has a short access time compared with the first recording mediumand in which, when a desired video and/or sound signal is recorded inthe first recording medium or reproduced from the first recordingmedium, a signal from a starting part of the video and/or sound signalto a predetermined time is recorded or reproduced, and controlling meansfor controlling the recording and reproducing means and the secondrecording medium (see, for example, JP-A-9-161461).

However, the same time lag occurs when reproduction of content isstarted from the middle of the content. Thus, it is desirable to make itpossible to reduce occurrence of a waiting time in reading out anarbitrary portion of the content.

SUMMARY OF THE INVENTION

According to an embodiment of the invention, there is provided a readoutdevice including a first recording medium having recorded therein dataof arbitrary plural portions of a period of a predetermined length intemporally continuous content; a second recording medium having recordedtherein data of the entire content; and readout controlling means forcontrolling, when the readout of data of the content is requested, thereadout of data from the first recording medium and from the secondrecording medium such that data of any one of the portions recorded inthe first recording medium is read out and data following the data readout from the first recording medium is read out from the secondrecording medium.

In this embodiment, data of arbitrary plural portions, which areportions of a period of a predetermined length in temporally continuouscontent, is recorded in the first recording medium, data of the entirecontent is recorded in the second recording medium, and, when thereadout of the data of the content is requested, the readout of the datafrom the first recording medium and from the second recording medium iscontrolled such that data of any one of the portions recorded in thefirst recording medium is read out and data following the data read outfrom the first recording medium is read out from the second recordingmedium.

Data of one entire content may be recorded in any one of plural secondrecording media. The readout device may further include readout meansfor reading out the data from the second recording medium; mountingmeans for mounting the second recording medium in the readout means; andmounting controlling means for controlling the mounting means, in aperiod in which data is read out from the first recording medium, tomount in the readout means, from among the plural second recordingmedia, the second recording medium having recorded therein datafollowing the data read out from the first recording medium.

The readout device may further include receiving means for receiving,according to an operation of a user, the designation of one portion atwhich the readout of data is started from among the plural portions inthe first recording medium. The readout controlling means may controlthe readout of data from the first recording medium and from the secondrecording medium such that data of the designated portion recorded inthe first recording medium is read out and data following the data readout from the first recording medium is read out from the secondrecording medium.

The readout controlling means may control the readout of data from thesecond recording medium such that data following the data read out fromthe first recording medium, which is data not recorded in the firstrecording medium, is read out from the second recording medium.

The readout controlling means may control the readout of data from thesecond recording medium such that the data is read out at a high readoutspeed compared with a normal readout.

The readout controlling means may control the readout of data from thefirst recording medium such that data read out from the second recordingmedium, which follows the data of portions recorded in the firstrecording medium in advance, is recorded in the first recording mediumfollowing the data of the respective portions and, then, data of aportion and data following the data of the portion are read out from thefirst recording medium.

The readout controlling means may record in the first recording mediumdata read out from the second recording medium which is not recorded inthe first recording medium in advance.

The readout controlling means may record data of the entire content inthe first recording medium on the basis of data read out from the secondrecording medium when the readout of data of the content is requested.

As described above, according to an embodiment of the invention, it ispossible to reduce the occurrence of a waiting time in reading out anarbitrary portion of the content.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a structure of a recording andreproducing system in the past;

FIG. 2 is a diagram for explaining processing for reproduction in thepast;

FIG. 3 is a block diagram showing a structure of a recording andreproducing system according to an embodiment of the invention;

FIG. 4 is a block diagram showing a more detailed structure of therecording and reproducing system;

FIG. 5 is a table for explaining information used in the recording andreproducing system;

FIG. 6 is a diagram for explaining a cache file recorded in a hard disk(HD);

FIG. 7 is a diagram for explaining the cache file recorded in the HD andreadout of data of content that uses the cache file;

FIG. 8 is a diagram for explaining readout of the data of the contentthat uses the cache file;

FIG. 9 is a diagram for explaining a cache file in a stub state;

FIG. 10 is a diagram for explaining areas and area information inextended attributes;

FIG. 11 is a diagram for explaining details of stub data;

FIG. 12 is a flowchart for explaining processing for writing hintinformation;

FIG. 13 is a flowchart for explaining processing for generating a cachefile in a stub file state;

FIG. 14 is a flowchart for explaining processing for reading out datafrom an index_n;

FIG. 15 is a flowchart for explaining details of processing of reload;

FIG. 16 is a diagram for explaining a specific example of the processingof reload;

FIG. 17 is a diagram for explaining the specific example of theprocessing of reload;

FIG. 18 is a block diagram showing another structure of the recordingand reproducing system according to the embodiment of the invention;

FIG. 19 is a diagram for explaining readout of data of content that usesa cache file;

FIG. 20 is a flowchart for explaining processing for reading out datafrom an index_n;

FIG. 21 is a block diagram showing still another structure of therecording and reproducing system according to the embodiment of theinvention; and

FIG. 22 is a block diagram showing an example of a structure of apersonal computer.

DETAILED DESCRIPTION

Embodiments of the invention will be hereinafter explained in detailwith reference to the accompanying drawings. An example of acorrespondence relation between elements described in claims andspecific examples in the embodiments of the invention is as describedbelow. This description is made for the purpose of confirming that thespecific examples supporting the inventions are described in theembodiments of the invention. Therefore, even if there is a specificexample described in the embodiments of the invention but not describedbelow as a specific example corresponding to an element, this does notmean that the specific example does not correspond to the element. Onthe other hand, even if a specific example is described as a specificexample corresponding to an element, this does not means that thespecific example does not correspond to elements other than the element.

Moreover, this description does not mean that the inventioncorresponding to a specific example described in the embodiments isdescribed in all the claims. In other words, this description does notdeny presence of an invention that corresponds to a specific exampledescribed in the embodiments and is not described in claims of thisapplication, that is, presence of an invention that will be added by adivisional application or amendment.

A readout device according to an embodiment of the invention includes: afirst recording medium (e.g., a hard disk (HD) 116 shown in FIG. 4)having recorded therein data of arbitrary plural portions, which areportions of a period of a predetermined length in temporally continuouscontent; a second recording medium (e.g., an optical disk 119 shown inFIG. 4) having recorded therein data of the entire content; and readoutcontrolling means (e.g., a hierarchical storage manager (HSM) 113) thatcontrols, when readout of data of the content is requested, readout ofdata from the first recording medium and the second recording mediumsuch that data of any one of the portions recorded in the firstrecording medium is read out and data following the data read out fromthe first recording medium is read out from the second recording medium.

A readout method according to another embodiment of the invention is areadout method for a readout device that reads out data from a firstrecording medium (e.g., the hard disk (HD) 116 shown in FIG. 4) havingrecorded therein data of arbitrary plural portions, which are portionsof a period of a predetermined length in temporally continuous content,and a second recording medium (e.g., the optical disk 119 shown in FIG.4) having recorded therein data of the entire content. The readoutmethod includes: a first control step (e.g., step S124 in FIG. 20) ofcontrolling, when readout of data of the content is requested, readoutof data from the first recording medium such that data of any one of theportions recorded in the first recording medium is read out; and asecond control step (step S129 in FIG. 20) of controlling readout ofdata from the second recording medium such that data following the dataread out from the first recording medium is read out from the secondrecording medium.

FIG. 3 is a block diagram showing a structure of a recording andreproducing system 101 according to an embodiment of the invention. Avideo/audio encoder 111 encodes, according to the Moving PicturesExperts Group (MPEG) system, image data of a baseband corresponding toan input image signal inputted. The video/audio encoder 111 encodes,according to the MPEG system, sound data of a baseband corresponding toa sound signal inputted (not shown). The video/audio encoder 111supplies data obtained by the encoding to a stream encoder 112.

The stream encoder 112 multiplexes the encoded data supplied from thevideo/audio encoder 111, converts the multiplexed data into a stream ofthe MPEG transport stream system or the MPEG program stream system, andsupplies the stream obtained by the conversion to a hierarchical storagemanager (HSM) 113.

The HSM 113 manages hierarchical recording of data of content in arecording medium (or manages recording of data of content in a recordingmedium having a hierarchical structure). The HSM 113 supplies the streamsupplied from the stream encoder 112 to a hard disk (HD) 116 via abuffer 115 under the control by the storage manager 114. The HD 116 isan example of a fast primary storage. The HD 116 records the stream(data) supplied from the HSM 113 via the buffer 115 under the control bythe HSM 113. The HD 116 supplies the stream (the data) recorded thereinto the buffer 115 or a buffer 117.

The buffer 115 includes a recording area of a part of a semiconductormemory or the HD 116. The buffer 115 temporarily stores the stream (thedata) supplied from the HSM 113 or the HD 116 and supplies the stream(the data) stored therein to the HSM 113 or the HD 116. The buffer 117includes a recording area of a part of the semiconductor memory or theHD 116. The buffer 117 temporarily stores the stream (the data) suppliedfrom the HD 116 or a drive 118 and supplies the stream (the data) storedtherein to the HD 116 or the drive 118.

The buffer 115 and the buffer 117 absorb readout jitters and planarizeda data rate to be fixed.

The drive 118 records the data supplied from the buffer 117 in anoptical disk 119 mounted therein as a file. The optical disk 119 is anexample of a slow secondary storage, for example, a magneto-optical disk(MO), a digital versatile disc (DVD), or a compact disc (CD).

A juke system 120 controls mounting of the optical disk 119 in the drive118 and unmounting of the optical disk 119 from the drive 118. The jukesystem 120 causes a picker 122 to select any one of optical disks 119from disk slots 121 storing the respective optical disks 119. The picker122 conveys the optical disk 119 selected and mounts the optical disk119 in the drive 118 under the control by the juke system 120. Thepicker 122 also conveys the optical disk 119 unmounted from the drive118 and stores the optical disk 119 in any one of the disk slots 121under the control by the juke system 120. In other words, the jukesystem 120 controls the picker 122.

The drive 118 reads out the data recorded as the file from the opticaldisk 119 mounted therein and supplies the data read out to the buffer117. The data read out from the optical disk 119 is supplied to the HD116 via the buffer 117 and recorded in the HD 116.

The HSM 113 reads out the data (the stream), which is read out from theoptical disk 119 and recorded in the HD 116, from the HD 116 via thebuffer 115 and supplies the data (the stream) read out to a streamdecoder 123.

The stream decoder 123 separates the stream in the MPEG transport streamsystem or the MPEG program stream system into image data and sound dataand supplies the image data and the sound data separated to avideo/audio decoder 124.

The video/audio decoder 124 decodes the image data and the sound dataencoded into image data and sound data of a so-called baseband. Thevideo/audio decoder 124 supplies an output image signal and sound signal(not shown), which are based on the image data and the sound data of thebaseband obtained by the decoding, to a monitor 125. The monitor 125displays an image on the basis of the output image signal and outputssound on the basis of the sound signal supplied.

In the video/audio encoder 111, in recording content, all data of thecontent corresponding to an input image signal inputted are recorded inthe HD 116. In an idle time of the drive 118, all the data of thecontent recorded in the HD 116 are copied to the optical disk 119. Inthis case, the HSM 113 records, in a store database described later,information indicating which data of the content is written in whichoptical disk 119. As described in detail later, this informationincludes information for identifying a file in which data of content isstored, information for identifying the optical disk 119 in which allthe data of the content are written, a date and time of the writing, ora name of the file in which the data of the content is stored.

A stream directly inputted from the outside may be recorded or thestream may be outputted. A system for encoding data is not limited tothe MPEG and only has to be an encoding system for predeterminedcompression and expansion. Moreover, a system for the stream does notlimit the invention.

FIG. 4 is a block diagram showing a more detailed structure of therecording and reproducing system 101. An application program 141 has afunction of an interface with a user and acquires an instruction fromthe user or notifies the user of various kinds of information concerningthe recording and reproducing system 101. The application program 141controls the entire recording and reproducing system 101.

For example, the application program 141 controls the video/audioencoder 111, the stream encoder 112, the video/audio decoder 124, thestream decoder 123, a content manager 142, and the storage manager 114according to operation by the user. The application program 141 acquiresan input image signal and sound signal from a video camera 171 andsupplies the input image signal and sound signal acquired to thevideo/audio encoder 111. The application program 141 acquires an outputimage signal and sound signal from the video/audio decoder 124 andsupplies the output image signal and sound signal acquired to themonitor 125. Moreover, the application program 141 supplies a stream(data) supplied from the HSM 113 via the storage manager 114 to thestream decoder 123.

The content manager 142 manages details of content recorded in therecording and reproducing system 101 and searches for the details of thecontent. The content manager 142 controls recording of various kinds ofinformation concerning the content in a content database (DB) 161 andcontrols readout of the information concerning the content from thecontent database 161.

As shown in FIG. 5, in the content database 161, information on a filerelated to the content (e.g., a file name and a pass name), details andadditional information of the content (e.g., a name of the content and agenre of the content), a compression form (system), a reproduction time,and index information (e.g., a position of an index in the content) ofthe content, user information of a user who can access the content(e.g., a name of the user and a password), and the like are recorded asinformation on the content.

The storage manager 114 controls the HSM 113 from the highest hierarchy.In other words, the storage manager 114 controls the HSM 113 on thebasis of a request from the application program 141. A system manager162 and a file I/O manager 163 are provided in the storage manager 114.

The system manager 162 sets a system related to storage control, recordsa system log, manages an error log, and executes maintenance processing.The file I/O manager 163 receives a request for readout or writing of afile from the application program 141. The file I/O manager 163instructs conversion of the file of the content recorded in the HD 116into, for example, a stub file (state) that holds data of a designatedpart, which is a part of image content or music content, as stub data.The file I/O manager 163 instructs suspension or resumption ofprocessing for readout of data from the optical disk 119 to the HD 116(reload described later). Moreover, the file I/O manager 163 instructssuspension or resumption of processing for writing of data in theoptical disk 119 from the HD 116.

The HSM 113 manages the HD 116, the drive 118, the optical disks 119,the juke system 120, the disk slots 121, and the picker 122 as a virtualstorage and controls temporary recording of data of content by the HD116. The HSM 113 includes a migration file system 164, a storage server165, a store database (DB) 166, a media server 167, and a volumedatabase (DB) 168.

The migration file system 164 manages extended attributes of a filemanaged by the HSM 113 and rewrites the extended attributes. Themigration file system 164 manages an access event to the file managed bythe HSM 113. The migration file system 164 controls processing forreading out data from the optical disks 119 to the HD 116 and controlsprocessing for writing data in the optical disks 119 from the HD 116.

The storage server 165 reads out data from the optical disks 119 to theHD 116 or writes data in the optical disks 119 from the HD 116. Thestorage server 165 manages recording of information on a cache file,which is recorded in the HD 116 and stores data of content, in the storedatabase 166 and manages readout of the information on the cache filefrom the store database 166. The storage server 165 manages the entiredata of the content and link information between the data and theoptical disks 119 in which the data is recorded.

The store database 166 records information on the cache file, which isrecorded in the HD 116 and stores data of content.

As shown in FIG. 5, association of a cache file name recorded in the HD116 and a cache file ID, which is a value for specifying a cache file,is stored in the store database 166. Cache file date informationindicating time when the cache file was written or time when the cachefile was accessed last and volume IDs for specifying the optical disks119 in which the entire data is stored are recorded in the storedatabase 166. Free capacities of the respective optical disks 119 in ajukebox 145 are recorded in the store database 166.

The media server 167 manages the optical disks 119 stored in therespective disk slots 121. The media server 167 requests a changerdriver 143 to mount a designated optical disk 119 in the drive 118. Themedia server 167 requests the changer driver 143 to store (unmount) theoptical disk 119 mounted in the drive 118 in the disk slot 121.

The volume database 168 provided in the media server 167 storesinformation related to the optical disks 119.

As shown in FIG. 5, recording capacities in a raw disk state of therespective optical disks 119, types (a magneto-optical disk (MO), adigital versatile disc (DVD)+R or DVD+RW, etc.) of the respectiveoptical disks 119 as media, and attributes such as write-only,read-writable, and the like are recorded in the volume database 168.Volume IDs of the optical disks 119 stored in the respective disk slots121 in the jukebox 145 and a state of use of the drive 118 mounted onthe jukebox 145 are recorded in the volume database 168.

The changer driver 143 controls the drive 118 and has a function of aninterface between a jukebox control unit 144 and the HSM 113.

The jukebox control unit 144 includes a juke system 120 and a juke servo169. The juke system 120 controls a system including the drive 118, theoptical disks 119, the juke system 120, the disk slots 121, and thepicker 122. The juke servo 169 drives the jukebox 145.

The jukebox 145 includes the drive 118, the optical disks 119, the diskslots 121, and the picker 122.

The data recorded in the content database 161, the store database 166,and the volume database 168 may be recorded in one database.

As shown in FIG. 5, area information concerning portions of the contentin a cache file, hint information indicating a hint on which portion ofthe content is recorded in the HD 116 as a cache file, and a cache fileID are recorded in the migration file system 164 as extended attributesof the content.

The extended attributes of the content may be recorded and read out by afile system of an operating system or may be recorded in the contentdatabase 161.

More specifically, the area information includes an offset indicating,for a portion of the content in the cache file, an offset value (byte)from the top of data of the content to the top of the portion, a sizeindicating a data amount of the portion of the content, and a flagindicating whether the portion of the content is stored or is in a holestate as described in detail later. The hint information includes a hintoffset indicating which portion of the content is recorded in the HD 116as a cache file and indicating an offset value (byte) from the top ofthe data of the content to the top of the portion, a hint sizeindicating a data amount of the portion of the content, a region flagindicating attributes of the portion as described in detail later, and ahint priority indicating a priority in migrating this portion.

Moreover, as shown in FIG. 5, information indicating whether the contentis read-only or read-writable is recorded by the file system.

A cache file recorded in the HD 116 and readout of data of content thatuses the cache file will be explained with reference to FIGS. 6 to 11.

FIG. 6 is a diagram for explaining states of the cache file recorded inthe HD 116. A stream (content) encoded by the video/audio encoder 111and multiplexed by the stream encoder 112 is written in (a cache area)of the HD 116 as a cache file. A state of the cache file in which dataof the entire stream (the entire content) inputted is recorded as shownin FIG. 6, is referred to as a regular state.

The entire content is recorded in the HD 116 and recorded in the opticaldisks 119 by shadowing for writing the cache file in the regular staterecorded in the HD 116, which is executed in an idle time of the jukebox145. A state of the cache file at the time when the data of the entirecontent is recorded in the HD 116 and recorded in the optical disks 119is referred to as a bit file state.

When the cache file is in the regular state or the bit file state, inother words, when the entire stream, that is, the entire data of thecontent is recorded in the HD 116, the entire data of the content isread out from the HD 116. Thus, it is possible to read out the data ofthe content at high speed. However, when the cache file is in theregular state or the bit file state, since a data amount of the cachefile is large, if the cache file in the regular state or the bit filestate is recorded in the HD 116 for a large number of contents, anamount of consumption of recording areas of the HD 116 increases toinstantly fill the HD 116 (comes into a state in which data is recordedin all the recording areas of the HD 116).

Thus, for example, it is possible to keep a total amount of data amountsof cache files recorded in the HD 116 within a fixed range by recordingthe data of the entire content in the optical disks 119 in order from anoldest cache file with reference to elapsed times since the cache filesare recorded in the HD 116 and reducing the data amounts of the cachefiles recorded in the HD 116.

A state of the cache file in which the data of the entire content is notrecorded but a predetermined portion of the data of the content isrecorded as shown in FIG. 6 is referred to as a stub file state. Inparticular, a state of the cache file in which plural portions, whichare predetermined portions, of the data of the content are stored isreferred to as multi-stub state. A state in which the data of the entirecontent is eliminated from the cache file and only the extendedattributes of the content and the cache file ID are recorded in the HD116 is exceptionally referred to as a zero stub state.

Reading out the data of the content from the optical disks 119 in whichthe data of the entire content is recorded and recording the data readout in the HD 116 is referred to as reload. For example, it is possibleto read out the data of the content from the optical disks 119 andrecord the data of the entire content in the HD 116.

As shown in FIG. 7, data corresponding to an input image signal andsound signal acquired from the application program 141 is recorded inthe HD 116 and the data recorded in the HD 116 is recorded in theoptical disk 119 mounted in the drive 118. In reading out this data, thedata is read out from the HD 116 or read out from the optical disk 119mounted in the drive 118 by the drive 118. The data read out from theoptical disk 119 by the drive 118 is temporarily recorded in the HD 116and read out to the application program 141 from the HD 116.

More specifically, in reading out data, as shown in FIG. 8, the data isread out from the optical disk 119 mounted in the drive 118 by the drive118 and temporarily stored in the buffer 117. The data temporarilystored in the buffer 117 is supplied to the HD 116 and recorded by theHD 116.

Data recorded in the HD 116 in advance (data in a stub area describedlater) is read out to the buffer 115 and temporarily stored in thebuffer 115. Similarly, data read out from the optical disk 119 via thebuffer 117 and recorded in the HD 116 in response to a request forreading out data (data in a hole area described later) is also read outto the buffer 115 and temporarily stored in the buffer 115.

The application program 141 reads out the data temporarily stored in thebuffer 115 and outputs an output image signal and sound signal.

FIG. 9 is a diagram for explaining a cache file in a stub state. A cachefile in the bit file state is shown in FIG. 9 for comparison. As shownin FIG. 9, data of entire content is stored in the cache file in the bitfile state and data of portions of content is stored in the cache filein the stub state.

For example, data of portions of the content in positions correspondingto indexes indicated by index information are stored in the cache filein the stub state. Index information indicates an index 1 in a startposition of the content, an index 2 in a position where twenty-threeminutes and twenty-six seconds have elapsed from the start of thecontent, an index 3 in a position where thirty-eight minutes andforty-five seconds have elapsed from the start of the content, and anindex 4 in a position where forty-three minutes fifty-nine seconds haveelapsed from the start of the content. In this case, data of a portionof the content in a predetermined period in the start position of thecontent, data of a portion of the content in a predetermined period inthe position where twenty-three minutes and twenty-six second haveelapsed from the start of the content, data of a portion of the contentin a predetermined period in the position where thirty-eight minutes andforty-five seconds have elapsed from the start of the content, and dataof a portion of the content in a predetermined period in the positionwhere forty-three minutes and fifty-nine seconds have elapsed from thestart of the content are stored in the cache file as stub data.

Length of time of the content reproduced by the stub data is set longerthan time necessary for unmounting the optical disk 119 stored in thedisk slot 121 from the disk slot 121, mounting the optical disk in thedrive 118, and reading out the data of the content from the optical disk119 mounted in the drive 118. For example, the length of time is set toabout twenty seconds to thirty seconds.

The stub means a portion of the content corresponding to the datarecorded in the cache area of the HD 116 as a cache file. The stub areameans an area on the content, stub data of which is recorded in the HD116, that is, an area of the stub. The hole area is an area on thecontent, stub data of which is not recorded in the HD 116.

When the stub area and the hole area are not distinguished, the areasare simply referred to areas. In FIG. 9, data in an area that is a stubarea indicated by 0 (stub data) corresponding to the index 1 is recordedin the HD 116 as a cache file. Data in an area that is a hole areaindicated by 1 between the index 1 and the index 2 is not recorded inthe HD 116. Similarly, data in an area that is a stub area indicated by2 (stub data) corresponding to the index 2, data in an area that is astub area indicated by 4 (stub data) corresponding to the index 3, anddata in an area that is a stub area indicated by 6 (stub data)corresponding to the index 4 are recorded in the HD 116 as cache files.Data in an area that is a hole area indicated by 3 between the index 2and the index 3, data in an area that is a hole area indicated by 5between the index 3 and the index 4, and data in an area that is a holearea indicated by 7 behind the index 6 are not recorded in the HD 116.

Areas and area information in extended attributes will be explained withreference to FIG. 10. In an example shown in FIG. 10, a stub area isarranged at the top of data of content. A hole area is arranged tofollow the stub area. A stub area is arranged to follow the hole areaand a hole area is arranged to follow the stub area. In other words,stub data, which is data in a portion at the top of the content, isrecorded in the cache file of the HD 116 (is set as stored) and data inan area following the portion of the top of the content, which is anarea having a predetermined length, is not recorded in the cache file ofthe HD 116 (is brought into the hole state). Stub data, which is data ina predetermined portion of the content following the area in the holestate, is recorded in the cache file of the HD 116 (is set as stored)and data in an area following the portion, which is an area having apredetermined length, is not recorded in the cache file of the HD 116(is brought into the hole state). In other words, an area in which dataof a portion of the content is recorded in the cache file of the HD 116and an area in which data of a portion of the content is not recorded inthe cache file of the HD 116 are alternately arranged.

The area information includes an area number, an offset, a size, and aflag of each of the areas. The area number takes continuous values of 0to N (an integer) from the top of the file. In other words, the areanumber is a serial number of an integer added to each of the areas inorder from the top of the data of the content with 0 as an initialvalue. The offset indicates an offset value from the top of the file(the top of the data of the content) to the top of the area. The offsetis, for example, in byte units. The size indicates a data amount of thedata in the area. The size is, for example, in byte units. The flagindicates a stub area (stored) or a hole area (the hole state). Forexample, a flag of 1 indicates a stub area (stored) and a flag of 0indicates a hole area (the hole state).

For example, a stub area at the top of the data of the content islocated at the top of the data of the content and has a data amount of150 bytes. Since this area is a stub area (in which data is stored), anarea number 0, an offset 0, a size 150, and a flag 1 are affixed to thestub area at the top of the data of the content. Since an area secondfrom the top of the data of the content has an original data amount of800 bytes and is a hole area (the content is in the hole state), an areanumber 1, an offset 150, a size 800, and a flag 0 are affixed to thisarea.

Similarly, since an area third from the top of the data of the contenthas a data amount of 150 bytes and is a stub area (in which data isstored), an area number 2, an offset 950 (150+800), a size 150, and aflag 1 are affixed to this area. Since an area fourth from the top ofthe data of the content has an original data amount of 1400 bytes and isa hole area (the content is in the hole state), an area number 3, anoffset 1100 (950+150), a size 1400, and a flag 0 are affixed to thisarea.

In this way, the area information in the extended attributes of thecontent indicates states of the respective areas in the cache file. Itis possible to learn states of the areas in the cache file by referringto the area information.

FIG. 11 is a diagram for explaining details of the stub data recorded inthe HD 116. In the file system of the operating system, data is recordedin the HD 116 with a sector size, which is a minimum unit of recordingin the HD 116, as a reference. When data (a stream) of content isrecorded in the HD 116, a boundary of sectors and a boundary of imagedata or sound data in the data (the stream) of the content (e.g., aboundary of units of encoding) do not always coincide with each other.

When the stub data is left in a cache file, data recorded in a sector ina range designated by the application program 141 is sliced as stubdata. This stub data is generated to be sectioned in sector units.

When a portion in the middle of the data of the content is sliced asstub data, the top of the stub data and the top of the boundary of thestream do not coincide with each other in many cases. For example, whena compression system for the content is the MPEG2, a boundary of a groupof pictures (GOP) does not always coincide with the top of the stubdata.

In the recording and reproducing system 101, when content is reproduced,even when data, the top of which does not coincide with the top of aboundary of a stream, is read out by the HSM 113 and supplied to thestream decoder 123, the stream decoder 123 detects a boundary of astream appearing first from the top of the stub data (e.g., the top ofthe GOP) and separates the data. Thus, the video/audio decoder 124 cancorrectly decode the data separated.

In other words, when stub data in a range designated by the applicationprogram 141 (a hint section described later) is left in the cache fileor when the stub data is reloaded to the cache file, the HSM 113 recordsstub data necessary for reproducing the entire range designated in theHD 116. The HSM 113 also records stub data having a data amount aninteger times as large as a recording capacity of a sector, whichincludes data of content necessary for reproducing the entire rangedesignated, in the HD 116.

When stub data in a range designated by the application program 141 (ahint section described later) is erased (deleted) from the cache file,the HSM 113 erases the stub data, which is the data of the contentnecessary for reproducing the entire range, recorded in the HD 116 fromthe HD 116. Moreover, the HSM 113 erases the stub data having a dataamount an integer times as large as a recording capacity of the sector,which includes the data of the content necessary for reproducing theentire range, recorded in the HD 116 from the HD 116.

In this way, when the stub data is left in the cache file or when thestub data is reloaded to the cache file, to record data of contentnecessary for reproducing an entire portion of a period of apredetermined length, the HSM 113 controls recording of the data of thecontent in the HD 116. To record data of content, which includes thedata of the content necessary for reproducing the entire portion of theperiod of the predetermined length and has a data amount an integertimes as large as a recording unit in the HD 116, the HSM 113 alsocontrols recording of the data of the content in the HD 116.

When the stub data is erased (deleted) from the cache file, to erase thedata of the content necessary for reproducing the entire portionrecorded in the HD 116, the HSM 113 controls recording of the data ofthe content in the HD 116. To erase the data of the content, whichincludes the data of the content necessary for reproducing the entireportion of the period of the predetermined length and has a data amountan integer times as large as the recording unit in the HD 116, the HSM113 also controls recording of the data of the content in the HD 116.

A sector size is 4 KB to 16 KB in Linux (trademark) and a data amount ofdata to be sliced is several tens MB. Thus, there is little influencedue to a way of sectioning boundaries of sectors.

Processing for writing hint information will be explained with referenceto a flowchart in FIG. 12. In step S11, the application program 141acquires index information indicating positions of indexes in contentfrom the content database 161 via the content manager 142. In step S12,the application program 141 specifies positions on the content indicatedby the indexes on the basis of the index information.

In step S13, the application program 141 generates hint information withthe positions specified as start positions of hint sections. The hintsections are portions (ranges) in the content indicated by the hintinformation.

The hint information is information indicating a hint on which portionof content is recorded in the HD 116 as a cache file. It is possible torecord data of arbitrary portions of the data of the content in a cachearea of the HD 116 as stub data. In other words, data of a portionsindicated by the hint information of the data of the content is storedin the cache file and recorded in the HD 116 as stub data. It ispossible to execute stepwise processing of migration by referring to thehint information.

The hint information includes a version number, a hint section length, ahint offset, a hint size, a region flag, a hint priority, and a timestamp. One version number and one hint section length are arranged inone piece of hint information. A hint offset, a hint size, a regionflag, a hint priority, and a time stamp corresponding to the number ofhint sections are arranged in one piece of hint information. In otherwords, one set of a hint offset, a hint size, a region flag, a hintpriority, and a time stamp indicates information on one area.

The version number indicates a version of hint information and is usedfor keeping compatibility of a system and software. The hint sectionlength indicates a total of data amounts of all hint sections indicatedby this hint information. When it is assumed that a data amount of onehint section is fixed, it is possible to calculate the number of hintsections by dividing the hint section length by the data amount of onehint section.

The hint offset indicates a start position of each of the hint sectionsas an offset from the top of the data of the content. For example, aunit of the hint offset is set as a data amount (byte, etc.). The hintsize indicates a data amount of the hint section. A unit of the hintsize is set as, for example, byte.

The region flag indicates, for each of the hint sections, an attributeconcerning, for example, whether the hint section is a hint sectioncorresponding to an index, a section corresponding to a climax scene, ora hint section corresponding to an important scene. The operating systemor the like can generate an event according to an access with referenceto the region flag.

The hint priority indicates a priority in migrating each of the hintsections. As a value of the hint priority is larger, data of a portioncorresponding to the hint section is more easily migrated. When 0 is setin the hint priority, the data of the portion corresponding to the hintsection is cached in the HD 116 serving as the primary storage until thecontent is deleted from the recording and reproducing system 101. It ispossible to manage a value of the hint priority, for example, set 0 to ahint priority of a hint section corresponding to a portion (data) of thecontent frequently accessed, using the application program 141 or theoperating system.

The time stamp indicates a date and time when the portion (the data) ofthe content corresponding to the hint section was accessed last. Thetime stamp is set by the application program 141 or the operatingsystem.

For example, the application program 141 sets a predetermined value asthe version number.

For example, the application program 141 calculates, from a position onthe content that is time in reproduction of the content specified by theprocessing in step S12, a data amount from the top of the data of thecontent to the position. The application program 141 sets the dataamount as a hint offset. For example, the application program 141 sets apredetermined value as a hint size. Moreover, for example, theapplication program 141 sets a predetermined value indicatingcorrespondence to an index as a region flag.

Furthermore, the application program 141 sets a predetermined value as ahint priority. For example, the application program 141 sets a valuethat is 0 for a first index of the content and is 1 for the otherindexes as a hint priority. The application program 141 sets a date andtime when the data of the content was accessed last as a time stamp.

The application program 141 sets a value obtained by multiplying thenumber of hint sections by the hint size as a hint section length.

The application program 141 generates hint information by arranging, ina predetermined order, the version number, the hint section length, thehint offset, the hint size, the region flag, the hint priority, and thetime stamp generated in this way.

In step S14, the application program 141 stores the hint information inthe extended attributes of the content recorded in the migration filesystem 164 of the HSM 113 via the storage manager 114.

In step S15, the application program 141 judges whether there isinformation indicating a climax scene in the content database 161 on thebasis of a result obtained by inquiring the content manager 142 aboutthe information. When it is judged in step S15 that there is informationindicating a climax scene, the application program 141 proceeds to stepS16. The application program 141 acquires the information indicating theclimax scene from the content database 161 via the content manager 142.

In step S17, the application program 141 specifies a position of the topof the climax scene on the content on the basis of the informationindicating the climax scene. For example, the application program 141specifies a position of the top of the climax scene, which depends ontime in reproduction of the content, on the basis of the informationindicating the climax scene.

In step S18, the application program 141 generates hint information withthe position at the top of the climax scene as a start position of ahint section. In step S19, the application program 141 stores the hintinformation in the extended attributes of the content recorded in themigration file system 164 of the HSM 113 via the storage manager 114 tocomplete the processing.

When it is judged in step S15 that there is no information indicating aclimax scene, the storage manager 114 skips the processing in steps S16to S19 to complete the processing.

In this way, the hint information is generated on the basis of the indexinformation and the information indicating the climax scene andrecorded. By giving the hint information to the content (the data of thecontent), it is possible to cache data of arbitrary portions in the dataof the content in the HD 116 as stub data and more quickly performreadout of the data of the content.

It is possible to perform stepwise processing of migration withreference to the hint information recorded in this way.

A value corresponding to operation by the user may be directly set inthe hint information. The hint information may be written by otherprograms such as the operating system other than the application program141.

FIG. 13 is a flowchart for explaining processing for generating a cachefile in a stub file state. In step S31, the storage manager 114 readsout the extended attributes of the content from the migration filesystem 164 of the HSM 113 and judges whether there is hint informationin the extended attributes of the content. When it is judged in step S31that there is hint information, the storage manager 114 proceeds to stepS32. The storage manager 114 reads out the extended attributes of thecontent from the migration file system 164 of the HSM 113 and extractsthe hint information from the extended attributes of the content readout. The storage manager 114 acquires a hint selection length indicatinga total of data amounts of all hint sections in the hint information.

In step S33, the storage manager 114 calculates the number of hintsections by dividing the hint section length by a data amount of onehint section.

In steps S34 and S42, the storage manager 114 executes processing insteps S35 to S41 for the respective hint sections and executesprocessing for loop control to repeat the processing in steps S34 to S42by the number of hint sections.

In step S35, the storage manager 114 acquires a hint offset indicating astart position of a predetermined hint section from the hintinformation. In step S36, the storage manager 114 acquires a hint sizeindicating a data amount of the hint section from the hint information.In step S37, the storage manager 114 acquires a hint priority indicatinga priority of the hint section from the hint information.

In step S38, the storage manager 114 sets an area in which the hintinformation is not set as a hole area that is deleted from the cachefile recorded in the HD 116.

In step S39, the storage manager 114 judges whether the hint priority isequal to or lower than a migration level set. When it is judged in stepS39 that the hint priority is equal to or lower than the migration levelset, the storage manager 114 proceeds to step S40. The storage manager114 sets the hint section for which the hint priority is set as a stubarea (an area to be cached).

The migration level is a reference for determining whether the hintsection is cached. For example, the storage manager 114 stores apredetermined migration level or determines a migration level on thebasis of a date and time when the content was accessed last included inthe file attributes. The storage manager 114 may perform processing ofjudgment on the basis of a migration level supplied from the applicationprogram 141 according to operation by the user.

As explained with reference to FIG. 11, when data is stored in a file ordata is read out from a file in recording units of a fixed length suchas a sector by the file system or the like of the operating system, instep S40, the storage manager 114 sets an area including the hintsection for which the hint priority is set as a stub area (an area to becached).

On the other hand, when it is judged in step S39 that the hint priorityis not equal to or lower than the migration level set, the storagemanager 114 proceeds to step S41. The storage manager 114 sets a hintsection for which the hint priority is set as a hole area that isdeleted from the cache file.

In this case, as explained with reference to FIG. 11, when data isstored in a file or data is read out from a file in recording units of afixed length such as a sector by the file system or the like of theoperating system, in step S41, the storage manager 114 sets an areaincluding the hint section for which the hint priority is set as a holearea.

The processing in steps S35 to S41 is executed for the respective hintsections. The areas including the respective hint sections are set asstub areas or set as hole areas. An area in which hint information isnot set is set as a hole area.

After repeating the processing in steps S34 to S42 by the number of hintsections, the storage manager 114 proceeds to step S44.

When it is judged in step S31 that there is no hint information in theextended attributes of the content, the storage manager 114 proceeds tostep S43. The storage manager 114 sets a file internal area inaccordance with initial setting. In other words, in step S43, thestorage manager 114 sets an area of the content as a stub area or a holearea in accordance with the initial setting and proceeds to step S44.

In step S44, the storage manager 114 judges whether data of a hole areais recorded in the cache file, that is, whether data of a hole area iscached. When it is judged that data of a hole area is cached, thestorage manager 114 proceeds to step S45. The storage manager 114 causesthe HSM 113 to delete (erase) the data of the hole area from the cachefile. The HSM 113 erases the data of the hole area from the cache fileof the HD 116 under the control by the storage manager 114. Thereafter,the storage manager 114 proceeds to step S46.

When it is judged in step S44 that the data of the hole area is notcached, it is unnecessary to execute processing for deleting data fromthe cache file. Thus, the processing in step S45 is skipped and thestorage manager 114 proceeds to step S46.

In step S46, the storage manager 114 judges whether data of a stub areais recorded in the cache file, that is, whether data of a stub area iscached. When it is judged that data of a stub area is not cached, thestorage manager 114 proceeds to step S47 and causes the HSM 113 toreload data of a stub area to the cache file. The HSM 113 mounts theoptical disk 119 having data of the entire content stored therein in thedrive 118 under the control by the storage manager 114. The HSM 113causes the drive 118 to read out data of the content from the opticaldisk 119 and stores the data of the content read out in the cache fileof the HD 116 to thereby reload the data of the stub area. Thereafter,the storage manager 114 proceeds to step S48.

When it is judged in step S46 that data of a stub area is cached, it isunnecessary to execute processing of reloading data of a stub area.Thus, the storage manager 114 skips the processing in step S47 andproceeds to step S48.

In step S48, the storage manager 114 causes the migration file system164 of the HSM 113 to rewrite area information of the extendedattributes of the content to be associated with a result of the erasureof the data from the cache file or the reload of the data to the cachefile to complete the processing.

As described above, the cache file in the stub file state is generated.

In this way, it is possible to execute the stepwise processing ofmigration on the basis of hint priorities.

By adding a hint priority of a desired value to a hint section andapplying processing for generating a cache file in the stub file state,which is based on a migration level of a desired value, to a cache file,it is possible to easily and flexibly select a portion to be cachedamong the data of the content.

For example, it is possible to increase speed of readout processing byallocating an optimum storage area according to a type of content. Forexample, when the type of the content is image content or music content,for example, it is possible to reduce an amount of use of a recordingarea of the primary storage traded at a high price per recordingcapacity such as the HD 116 by arranging stub areas according to indexesof the content. Time during which the stub areas are accessed concealstime during which data of the entire content is reloaded to the primarystorage. Thus, the user is not kept waiting for a long time from timewhen the user instructs access to the content until time when output isstarted. It is possible to provide the user with the content withoutcausing the user to feel stress due to waiting.

As explained with reference to FIG. 12, hint information correspondingto index information (chapter information) is generated, hintinformation corresponding to climax scenes is generated, and stub datais recorded in a cache file on the basis of the hint information. Inthis case, in the application program 141, if the user can instructreproduction of the indexes or the climax scenes easier than the otherportions of the content, or if the user is guided to access the indexesor the climax scenes, it is possible to more surely output the contentpromptly without causing the user to wait for a long time.

The content is not limited to the image content and the music content.Content such as a game may be recorded. In this case, a specific datafile or a portion of data of the content such as a game is recorded inthe HD 116.

Processing for reading out the data of the content, which uses the cachefile in the stub file state generated in this way, will be explained.

FIG. 14 is a flowchart for explaining processing for reading out datafrom an index_n. In step S61, the file I/O manager 163 of the storagemanager 114 receives designation of the index_n for starting readout ofdata. More specifically, the application program 141 receives selectionof an index for starting reproduction corresponding to operation by theuser. The application program 141 is selected by the user and suppliesdata designating the index for starting reproduction to the file I/Omanager 163. The file I/O manager 163 acquires the data from theapplication program 141 to receive the designation of the index_n forstarting readout of the data selected by the user. The storage manager114 instructs the HSM 113 to reproduce the content from the index_n.

In step S62, the storage manager 114 judges, on the basis of the areainformation stored in the migration file system 164 of the HSM 113,whether all data of the content instructed to be read out are recordedin the HD 116 as a cache file, that is, whether all data of the contentinstructed to be read out are stored in the HD 116. When it is judged instep S62 that all the data are stored in the HD 116, the storage manager114 proceeds to step S63. The storage manager 114 instructs the HSM 113to read out data of the content from a position corresponding to theindex_n. The HSM 113 causes the HD 116 to start readout of data of thecache file from the position corresponding to the index_n. After theprocessing in step S63, the storage manager 114 proceeds to step S69.

On the other hand, when it is judged in step S62 that all the data arenot stored in the HD 116, the storage manager 114 proceeds to step S64.The storage manager 114 instructs the HSM 113 to read out data of thecontent from the position corresponding to the index_n. The HSM 113causes the HD 116 to start readout of the data from a front position ofa stub area corresponding to the index_n of the cache file of the HD116.

Consequently, the content is immediately reproduced.

The storage manager 114 issues a reload command, which is a request forreading out corresponding data of the content from the optical disk 119to the HD 116, to the HSM 113.

In step S65, the HSM 113 refers to a cache file ID and a volume IDcorresponding to the reload command from the store database 166. In stepS66, the storage server 165 specifies, on the basis of the volumedatabase 168, the disk slot 121 in which the optical disk 119 specifiedby the volume ID is stored. In other words, the storage server 165requests the media server 167 to specify the disk slot 121 in which theoptical disk 119 specified by the volume ID is stored. The media server167 causes the volume database 168 to search for a volume ID coincidingwith the volume ID included in a request from the storage server 165among volume IDs for specifying the optical disks 119 stored in therespective disk slots 121 of the jukebox 145. The volume database 168outputs information indicating the disk slot 121 in which the opticaldisk 119 specified by the volume ID included in the request from thestorage server 165 is stored. Thus, the media server 167 suppliesinformation indicating the disk slot 121 to the storage server 165.Consequently, the storage server 165 specifies the disk slot 121 storedin the optical disk 119 specified by the volume ID.

In step S67, the storage server 165 instructs the media server 167 tomount the optical disk 119, which is stored in the disk slot 121specified, in the drive 118. The media server 167 causes the juke system120 to mount the optical disk 119, which is stored in the disk slot 121specified, in the drive 118 via the changer driver 143. In other words,the picker 122 of the jukebox 145 unmounts the optical disk 119 from thedisk slot 121 specified, conveys the optical disk 119, and mounts theoptical disk 119 in the drive 118 under the control by the juke system120.

In step S68, processing of reload is executed. Details of the processingof reload will be described later with reference to a flowchart in FIG.15.

After the processing in step S68, the storage manager 114 proceeds tostep S69.

In step S69, the storage manager 114 judges whether data has been readout to the end of the cache file. When it is judged that the data hasnot been read out to the end of the cache file, the storage manager 114returns to step S69 and repeats the processing of judgment.

When it is judged in step S69 that the data has been read out to the endof the cache file, the storage manager 114 completes the processing.

Details of the processing of reload in step S68 in FIG. 14 will beexplained with reference to a flowchart in FIG. 15. In step S81, thestorage manager 114 designates a predetermined position and instructsthe HSM 113 to start reload. The migration file system 164 of the HSM113 sets a start position for reload at the top of an area behind aposition of data currently read out from the HD 116 and closest to theposition of the data.

In step S82, the storage server 165 of the HSM 113 starts reload. Thestorage server 165 reads out data in the start position for reload fromthe drive 118 in which the optical disk 119 is mounted and causes the HD116 to record the data read out to be stored in a predetermined area ofthe cache file.

In step S83, the migration file system 164 judges whether data is storedin the area. When it is judged that data is stored in the area, in stepS84, the migration file system 164 moves the start position for reloadto the top of a hole area behind the area and closest to the area. Whenit is judged in step S83 that data is not stored in the area, themigration file system 164 skips the processing in step S84.

In step S85, the storage server 165 of the HSM 113 starts reload.

In step S86, the migration file system 164 judges whether the reload ofthe area has been completed. When it is judged that the reload of thearea has not been completed, the migration file system 164 returns tostep S86 and repeats the processing of judgment.

When it is judged in step S86 that the reload of the area has beencompleted, the migration file system 164 proceeds to step S87. Themigration file system 164 rewrites extended attributes to combine thearea for which the reload has been completed and a stub area adjacent tothe area.

In step S88, the migration file system 164 judges whether the reload hasbeen completed to the end of the cache file. When it is judged in stepS88 that the reload has been completed to the end of the cache file, themigration file system 164 proceeds to step S89. The migration filesystem 164 judges whether all the data of the content have been recordedin the HD 116, that is, whether all the data of the content have beenstored.

When it is judged in step S89 that all the data of the content have notbeen stored, the migration file system 164 proceeds to step S90. Themigration file system 164 judges whether the reload is performed in anauto-reload mode. When it is judged in step S90 that the reload isperformed in the auto-reload mode, the migration file system 164proceeds to step S91. The migration file system 164 moves the startposition for reload to the top of the cache file, returns to step S82,and repeats the processing described above.

When it is judged in step S88 that the reloaded has not been completedto the end of the cache file, the migration file system 164 returns tostep S82 and repeats the processing described above.

When it is judged in step S89 that all the data of the content have beenstored or it is judged in step S90 that the reload is not performed inthe auto-reload mode, the migration file system 164 completes theprocessing.

In this way, while the data of the content is read out from the cachefile of the HD 16 and before readout of data not recorded in the cachefile in advance is executed, data of hole areas is read out from theoptical disk 119 mounted in the drive 118 and the data read out isstored in the cache file. The drive 118 reads out the data from theoptical disk 119 at higher speed compared with readout speed for datanecessary for reproduction of the content. Thus, data not stored in thecache file of the HD 116 before the reproduction of the content isstarted is stored in the cache file of the HD 116 before being read outfor reproduction of the content. Therefore, it is possible to typicallyread out the data necessary for reproduction of the content from thecache file of the HD 116.

As a result, when readout of the data of the content is requested, it ispossible to quickly read out the data of the content while causinglittle waiting time. In other words, for example, in the case of contentof sound or an image, it is possible to reproduce the sound or the imagewithout interruption.

Moreover, since the data of the content is read from the optical disk119 first and, then, recorded in the HD 116, it is possible to releasethe drive 118 earlier compared with the case in which the data read outfrom the optical disk 119 is directly used for reproduction. In otherwords, it is possible to sufficiently show abilities of the drive 118such as fast readout of data from the optical disk 119 and moreefficiently use the drive 118.

FIGS. 16 and 17 are diagrams for explaining a specific example of theprocessing of reload. The processing of reload will be explained withreference to FIGS. 16 and 17. In the processing of reload, for content,stub data corresponding to respective three indexes of which arerecorded in a cache file, first, reproduction from an index 3 isrequested, reproduction from an index 2 is requested in the middle ofthe reproduction of the content, and the content continues to bereproduced to the end of the content.

When the user performs operation for selecting the index 3 as an indexfor starting reproduction, the application program 141 receivesselection of the index 3 by the user. First, under the control by thestorage manager 114, the HSM 113 causes the HD 116 to start readout ofdata from the front position of a stub area affixed with an area number4 corresponding to the index 3 of the cache file of the HD 116.Reproduction of the content is started from the index 3.

As shown in FIG. 17, 100-byte stub data of a portion at the top of thecontent, 100-byte stub data of a position 2500 bytes apart from the topof the content, and 100-byte stub data of a position 6000 bytes apartfrom the top of the content are recorded in the cache file inassociation with the index 1, the index 2, and the index 3. Data of theother portions of the content are not recorded in the cache file.

A stub area corresponding to the index 3, that is, the 100-byte stubdata of the position 6000 bytes apart from the top of the content isread out from the HD 116. Reproduction of the content is immediatelystarted from the index 3.

In parallel with the reproduction of the content, second, the storagemanager 114 causes the HSM 113 to read out data of a hole area behindthe stub area of the index 3 from the optical disk 119 to the HD 116 andissues a reload command indicating a request for recording the data inthe HD 116. Then, third, the optical disk 119 having recorded thereinthe data of the entire content started to be reproduced is mounted inthe drive 118. Fourth, at a point when it is possible to read out datafrom the optical disk 119 mounted, data of the content corresponding todata of a hole area (an area affixed with the area number 5) behind thestub area of the index 3 is read out from the optical disk 119 mountedin the drive 118. The reload of the data of the content is started suchthat the data read out is stored in a hole area behind the stub area ofthe index 3 (stored to follow behind the stub area of the index 3) ofthe cache file of the HD 116.

In this case, data following the 100-byte stub data of the position 6000bytes apart from the top of the content is read out from the opticaldisk 119 mounted in the drive 118. The data read out is reloaded to thehole area to follow the 100-byte stub data of the position 6000 bytesapart from the top of the content. Therefore, the data is stored inorder from the top of the area affixed with the area number 5. Themigration file system 164 updates the extended attributes to combine theportion stored with the area affixed with the area number 4 according tothe storage of the data.

Therefore, as the processing of reload progresses, an offset position ofthe area in the hole state to be subjected to the processing of reloadshifts to the rear side of the content (the offset increases) and a sizeof the area decreases.

When the user performs operation for selecting the index 2 as the indexfor starting reproduction, fifth, the application program 141 jumps tothe index 2. Sixth, under the control by the storage manager 114, theHSM 113 causes the HD 116 to start readout of data from the frontposition of the stub area corresponding to the index 2 of the cache fileof the HD 116. Reproduction of the content from the index 2 isimmediately started.

When a position for reading out data is changed by the applicationprogram 141 with an index as a unit, reload is performed from the top ofa hole area closest to the position from which the data is read outamong areas in the hold state (hole areas) behind the position fromwhich the data is read out. Thus, the processing of reload currentlyexecuted is suspended and the reload is resumed from the top of a holearea closest to a position from which the data is to be read out. Evenif the position from which the data is read out is changed, when theposition to which the data is currently reloaded is the top of a holearea closest to the position from which the data is read out among areasin the hole state (hole areas) behind the position changed, from whichthe data is read out, the processing of reload is continued.

For example, since the reproduction of the content is started from theindex 2, seventh, the processing of reload of the data of the hole areabehind the stub area of the index 3 is suspended.

For example, 1500-byte data following the 100-byte stub data of theposition 6000 bytes apart from the top of the content is read out fromthe optical disk 119 mounted in the drive 118. The 1500-byte data readout is reloaded to a hole area to follow the 100-byte stub data of theposition 6000 bytes apart from the top of the content. As a result, adata amount of a stub area in the position 6000 bytes apart from the topof the content is 1600 bytes (100+1500). The migration file system 164sets a size of the area indicated by the area number 4 included in thearea information of the extended attributes of the file to 1600.

Eighth, data of the content corresponding to the data of the hole areabehind the stub area of the index 2 is read out from the optical disk119 mounted in the drive 118. The reload of the data of the content isstarted such that the data read out is stored in the hole area behindthe stub area of the index 2 of the cache file of the HD 116.

Ninth, when the reload of the hole area behind the stub area of theindex 2 is completed, the areas in which data is already stored areskipped. Tenth, the processing of reload is continued such that reloadof the data of the position where the processing of reload is suspendedin the seventh processing, that is, the hole area behind the stub areaof the index 3 is performed.

3400-byte data following the 100-byte stub data of the position 2500bytes apart from the top of the content is read out from the opticaldisk 119 mounted in the drive 118. The 3400-byte data read out isreloaded to the hole area to follow the 100-byte stub data of theposition 2500 bytes apart from the top of the content. As a result,reload of a hole area next to the stub area in which the 100-byte stubdata of the position 2500 bytes apart from the top of the content isstored is completed. Thus, data from the position 2500 bytes apart fromthe top of the content to a position 7600 bytes apart from the top ofthe content are stored in the cache file. Consequently, the stub areaaffixed with the area number 2, the hole area affixed with the areanumber 3, and the stub area affixed with the area number 4, which areadjacent to one another, are combined into one stub area.

When an area number of the leading area is assumed to be 0, continuousvalues are reallocated as the area numbers of the respective areas. As aresult, an area number of the stub area combined is set to 2 and an areanumber of the hole area affixed with the area number 5 before combiningthe areas is set to 3.

According to the combination of the areas, a data amount of the stubarea affixed with the area number 2 is 5100 bytes (100+3400+1600). Themigration file system 164 sets a size of the area affixed with the areanumber 2 and an offset, a size, and a flag for the area affixed with thearea number 3, which are included in the area information of theextended attributes of the file, to 5100, 7600, 1400, and 0,respectively.

Reload of data of the hole area behind the stub area of the index 3,that is, the area affixed with the area number 3 according to thecombination of the areas is performed. When the data of the content isreloaded to the end, the area affixed with the area number 2 and thearea affixed with the area number 3 are combined.

In the auto-reload mode, when the data of the content is reloaded to theend, the remaining data not reloaded is reloaded to the cache file fromthe top to complete the processing. Thus, a position of the reload ismoved to the top of the cache file. Eleventh, the area in which the topof the content is stored is skipped. Twelfth, the processing of reloadis continued such that reload of the data of the hole area behind thestub area of the index 1 at the top of the content is performed.

As shown in FIG. 17, data following the 100-byte stub data at the top ofthe content is read out from the optical disk 119 mounted in the drive118. The data read out is reloaded to a hole area next to the stub dataat the top of the content.

Thirteenth, when data up to immediately before the stub area of theindex 2 is stored in the cache file, the data of the entire content isstored in the cache file. Thus, the reload is completed. In this case,all the areas are combined into one area. Fourteenth, the optical disk119 is unmounted from the drive 118 and returned to the disk slot 121.

In this way, when readout of the content, the cache file in the stubfile state of which is recorded in the HD 116, is requested, the data isread out from the optical disk 119 having recorded therein the data ofthe entire content. The data read out is stored in the cache file. Thedata stored in the cache file is read out and the content is reproduced.

As described above, it is possible to further reduce occurrence of awaiting time in reading out an arbitrary portion of the content.

It is also possible that data not recorded in the cache file is read outfrom the optical disk 119 and the content is directly reproduced fromthe data read out from the optical disk 119.

FIG. 18 is a block diagram showing another structure of the recordingand reproducing system 101 according to the embodiment of the inventionin this case. Components identical with those shown in FIG. 3 aredenoted by the identical reference numerals and signs. Explanations ofthe components are omitted.

The HD 116 supplies a stream (data) recorded therein to a buffer 201 ora selector 202.

The buffer 201 includes a recording area of a part of a semiconductormemory or the HD 116. The buffer 201 temporarily stores the stream (thedata) supplied from the HD 116 and supplies the stream (the data) storedtherein to the drive 118.

The selector 202 selects one of data outputted from the driver 118 anddata outputted from the HD 116 under the control by the HSM 113. Thebuffer 115 acquires one of the data outputted from the drive 118 and thedata outputted from the HD 116 selected by the selector 202 and storesthe data acquired.

The selector 202 may be provided as hardware. Alternatively, a functionequivalent to the selector 202 may be realized by software (processing).

The selector 202 may select one of the data outputted from the drive 118and the data outputted from the HD 116 under the control by the storagemanager 114.

When data not recorded in the cache file is read out from the opticaldisk 119 and the content is directly reproduced from the data read outfrom the optical disk 119, as shown in FIG. 19, the data stored in thecache file of the HD 116 is read out from the HD 116 and the data notstored in the cache file of the HD 116 is read out from the optical disk119, which is mounted in the drive 118, by the drive 118.

In other words, data of a stub area recorded in the HD 116 in advance isread out from the HD 116 to the buffer 115 and temporarily stored in thebuffer 115. Data of a hole area not recorded in the HD 116 in advance isread out from the optical disk 119, directly supplied to the buffer 115without being recorded by the HD 116, and temporarily stored in thebuffer 115.

The application program 141 reads out the data temporarily stored in thebuffer 115 and outputs an output image signal and sound signal.

FIG. 20 is a flowchart for explaining processing for reading out datafrom the index_n in the case in which the data not recorded in the cachefile is read out from the optical disk 119 and the content is directlyreproduced from the data read out from the optical disk 119. Sinceprocessing in steps S121 to S123 is the same as the processing in stepsS61 to S63 in FIG. 14, an explanation of the processing is omitted.

In step S124, the storage manager 114 instructs the HSM 113 to read outthe data of the content from a position corresponding to the index_n.The HSM 113 causes the HD 116 to start readout of the data from thefront position of a stub area corresponding to the index_n of the cachefile.

The storage manager 114 issues a command of a request for reading outthe data of the content from the optical disk 119 to the HSM 113.

In step S125, as in the processing in step S65, the HSM 113 refers to acache file ID and a volume ID corresponding to the command from thestore database 166. In step S126, as in the processing in step S66, thestorage server 165 specifies, on the basis of the volume database 168,the disk slot 121 in which the optical disk 119 specified by the volumeID is stored.

In step S127, as in the processing in step S67, the storage server 165instructs the media server 167 to mount the optical disk 119, which isstored in the disk slot 121 specified, in the drive 118. The mediaserver 167 causes the juke system 120 to mount the optical disk 119,which is stored in the disk slot 121 specified, in the drive 118 via thechanger driver 143.

In this way, the optical disk 119 is mounted in the drive 118 in thebackground while the data is read out from the cache file of the HD 116.

In step S128, the HSM 113 judges whether the readout of the data of thestub area, which is the data recorded in the HD 116, has been completed.When it is judged that the readout of the data of the stub area has notbeen completed, the HSM 113 returns to step S128 and repeats theprocessing of judgment. When it is judged in step S128 that the readoutof the data of the stub area has been completed, the HSM 113 proceeds tostep S129. The HSM 113 causes the drive 118 to start readout of the datafrom the optical disk 119 mounted therein. More specifically, themigration file system 164 of the HSM 113 sets a start position of thereadout of the data from the optical disk 119 as the top of a hole areabehind a position of the data being currently read out from the HD 116,which is a hole area closest to the position. The storage server 165causes the drive 118 in which the optical disk 119 is mounted to readout the data in the start position. The data read out from the drive 118is supplied to the stream decoder 123.

After the processing in step S129, the storage manager 114 proceeds tostep S130.

In step S130, the storage manager 114 judges whether the data has beenread out to the end of the content. When it is judged that the data hasnot been read out to the end of the content, the storage manager 114returns to step S130 and repeats the processing of judgment.

When it is judged in step S130 that the data has been read out to theend of the content, the storage manager 114 completes the processing.

Consequently, it is possible to further reduce accesses to the HD 116.It is also possible to further reduce an amount of use of the recordingarea of the HD 116.

After the optical disk 119 is mounted in the drive 118, it is possibleto quickly read out data of an arbitrary portion on the contentincluding hole areas.

The processing of the recording and reproducing system 101 shown in FIG.3 and the processing of the recording and reproducing system 101 shownin FIG. 18 may be adaptively switched.

Moreover, it is also possible to transmit recorded content via anetwork.

FIG. 21 is a block diagram showing still another structure of therecording and reproducing system according to the embodiment of theinvention that transmits recorded content via a network. Componentsidentical with those shown in FIG. 3 are denoted by the identicalreference numerals and signs. Explanations of the components areomitted.

In this case, the recording and reproducing system includes a server 301and a client 303 connected to the server 301 via a network 302.

The server 301 includes the HSM 113, the storage manager 114, theapplication program 141, the content manager 142, the changer driver143, the jukebox control unit 144, the jukebox 145, a streaming server321, and a network library 322.

The application program 141 receives a stream including image data andsound data transmitted from the client 303 via the network 302 andsupplies the stream received to the storage manager 163. The applicationprogram 141 causes the streaming server 321 to transmit the streamsupplied from the storage manager 163.

The streaming server 321 transmits the stream supplied from theapplication program 141 to the client 303 via the network 302 on thebasis of a procedure described as the network library 322. When data forrequesting reproduction of the content from a predetermined position (atransmission request for a stream) transmitted from the client 303 isreceived, the streaming server 321 transmits a stream for reproducingthe content from the requested position to the client 303 via thenetwork 302.

A procedure for transmitting or receiving a stream or data via thenetwork 302 is described in the network library 322.

The network 302 includes a local area network (LAN) such as a homenetwork, the Internet, a public line, a leased line, or the like using awireless or wired transmission medium and transmits various data(including streams).

The client 303 includes an application program 341, a streaming client342, a network client 343, a video/audio decoder 344, and a video/audioencoder 345.

The application program 341 has a function of an interface with a userand acquires an instruction from the user or notifies the user ofvarious kinds of information concerning the client 303. The applicationprogram 141 controls the entire client 303.

The streaming client 342 receives a stream transmitted from the server301 via the network 302 and supplies the stream received to thevideo/audio decoder 344. The network client 343 transmits various datato and receives various data from the server 301 via the network 302.The network client 343 transmits a stream supplied from the video/audioencoder 345 to the server 301 via the network 302. The network client343 transmits data for requesting reproduction of content from a desiredposition (a transmission request for a stream) to the server 301 via thenetwork 302.

The video/audio decoder 344 separates the stream into image data andsound data. The video/audio decoder 344 decodes image data and sounddata encoded into image data and sound data of a so-called baseband andsupplies an output image signal and sound signal (not shown) based onthe image data and the sound data of the baseband obtained by thedecoding to the monitor 125.

The video/audio encoder 345 acquires an input image signal and soundsignal from the video camera 171 and converts the input image signal andsound signal acquired into image data and sound data of a baseband. Thevideo/audio encoder 345 encodes the image data and the sound data of thebaseband and multiplexes the image data and the sound data encoded togenerate a stream. The video/audio encoder 345 supplies the streamgenerated to the network client 343.

In this way, the server 301 can quickly transmit the stream forreproducing the content from the desired position to the client 303 viathe network 302.

As described above, according to the invention, it is possible tofurther reduce occurrence of a waiting time in reading out an arbitraryportion of the content.

Other fast recording media such as a semiconductor memory may be used asthe primary storage instead of the HD 116. Other recording media tradedat a low price per recording capacity compared with the primary storagesuch as a magnetic disk and a magnetic tape may be used as the secondarystorage instead of the optical disk 119.

The series of processing described above can be executed by hardware orcan be executed by software. When the series of processing is executedby software, a program constituting the software is installed in acomputer built in dedicated hardware or, for example, a general-purposepersonal computer capable of executing various functions by installingvarious programs.

FIG. 22 is a block diagram showing an example of a structure of apersonal computer that executes the series of processing according to aprogram. A central processing unit (CPU) 401 executes various kinds ofprocessing in accordance with a program stored in a read only memory(ROM) 402, a recording unit 408, or a recording unit 409. Programsexecuted by the CPU 401, data, and the like are appropriately stored ina random access memory (RAM) 403. The CPU 401, the ROM 402, and the RAM403 are connected to one another by a bus 404.

As the CPU 401, it is possible to adopt the Cell described in “Cell isproduced”, Nikkei Electronics, Nikkei Business Publications, Inc., Feb.28, 2005, pages 89 to 117.

An input/output interface 405 is connected to the CPU 401 via the bus404. An input unit 406 including a keyboard, a mouse, and a microphoneand an output unit 407 including a display and a speaker are connectedto the input/output interface 405. The CPU 401 executes various kinds ofprocessing in response to instructions inputted from the input unit 406.The CPU 401 outputs results of the processing to the output unit 407.

The recording unit 408 connected to the input/output interface 405corresponds to, for example, the HD 116 and records the programsexecuted by the CPU 401 and the various data. The recording unit 409corresponds to, for example, the jukebox 145 and records the variousdata and the programs executed by the CPU 401. The communication unit410 communicates with external apparatuses such as the client 303 viathe network 302 such as the Internet or a LAN.

A program may be acquired via the communication unit 410 and recorded inthe recording unit 408 or the recording unit 409.

When a magnetic disk 421, an optical disk 422, a magneto-optical disk423, a semiconductor memory 424, or the like is mounted in a drive 411connected to the input/output interface 405, the drive 411 drives themagnetic disk 421, the optical disk 422, the magneto-optical disk 423,the semiconductor memory 424, or the like and acquires programs, data,and the like recorded therein. The programs and the data acquired aretransferred to the recording unit 408 or the recording unit 409 ifnecessary and recorded therein.

As shown in FIG. 22, a recording medium having stored therein theprogram for performing the series of processing is constituted bypackage media having the program recorded therein including the magneticdisk 421 (including a flexible disk), the optical disk 422 (including acompact disc-read only memory (CD-ROM) and a digital versatile disc(DVD)), the magneto-optical disk 423 (including a mini-disc (MD)(trademark)), the semiconductor memory 424, or the like that isdistributed to provide the user with the program separately from thecomputer. Besides, the recording medium is constituted by a ROM 402, ahard disk included in the recording unit 408, the optical disk 119included in the recording unit 409, or the like having the programrecorded therein that is provided to the user in a state in which theROM 402, the hard disk, the optical disk 119, or the like is built inthe computer in advance.

The program for executing the series of processing may be installed inthe computer via a wired or wireless communication medium such as alocal area network, the Internet, or a digital satellite broadcast and,if necessary, via an interface such as a router or a modem.

In this specification, steps describing the program stored in therecording medium includes not only processing performed in time seriesaccording to the order described but also processing executed inparallel or individually, although not always processed in time series.

In this specification, the system represents an entire apparatusincluding plural devices.

As described above, it is possible to reduce occurrence of a waitingtime in reading out an arbitrary portion of the content.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations, and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

1. A readout device, comprising: a first recording medium havingrecorded therein data of arbitrary plural portions of a period of apredetermined length in temporally continuous content; a secondrecording medium having recorded therein data of the entire content; andreadout control means for controlling, when the readout of data of thecontent is requested, the readout of data from the first recordingmedium and from the second recording medium such that data of any one ofthe portions recorded in the first recording medium is read out and datafollowing the data read out from the first recording medium is read outfrom the second recording medium.
 2. A readout device according to claim1, wherein data of one entire content is recorded in any one of pluralsecond recording media, the readout device further comprising: readoutmeans for reading out the data from the second recording medium;mounting means for mounting the second recording medium in the readoutmeans; and mounting controlling means for controlling the mountingmeans, in a period in which data is read out from the first recordingmedium, to mount in the readout means, from among the plural secondrecording media, the second recording medium having recorded thereindata following the data read out from the first recording medium.
 3. Areadout device according to claim 1, further comprising receiving meansfor receiving, according to an operation of a user, the designation ofone portion at which the readout of data is started from among theplural portions in the first recording medium, wherein the readoutcontrol means controls the readout of data from the first recordingmedium and from the second recording medium such that data of thedesignated portion recorded in the first recording medium is read outand data following the data read out from the first recording medium isread out from the second recording medium.
 4. A readout device accordingto claim 1, wherein the readout control means controls the readout ofdata from the second recording medium such that data following the dataread out from the first recording medium, which is data not recorded inthe first recording medium, is read out from the second recordingmedium.
 5. A readout device according to claim 1, wherein the readoutcontrol means controls the readout of data from the second recordingmedium such that the data is read out at a high readout speed comparedwith a normal readout.
 6. A readout device according to claim 1, whereinthe readout control means controls the readout of data from the firstrecording medium such that data read out from the second recordingmedium, which follows the data of portions recorded in the firstrecording medium in advance, is recorded in the first recording mediumfollowing the data of the respective portions and, then, data of aportion and data following the data of the portion are read out from thefirst recording medium.
 7. A readout device according to claim 6,wherein the readout control means records in the first recording mediumdata read out from the second recording medium which is not recorded inthe first recording medium in advance.
 8. A readout device according toclaim 6, wherein the readout control means records data of the entirecontent in the first recording medium on the basis of data read out fromthe second recording medium when the readout of data of the content isrequested.
 9. A readout method for a readout device that reads out datafrom a first recording medium having recorded therein data of arbitraryplural portions of a period of a predetermined length in temporallycontinuous content, and data from a second recording medium havingrecorded therein data of the entire content, the readout methodcomprising: controlling, when the readout of data of the content isrequested, the readout of data from the first recording medium such thatdata of any one of the portions recorded in the first recording mediumis read out; and controlling the readout of data from the secondrecording medium such that data following the data read out from thefirst recording medium is read out from the second recording medium. 10.A program that causes a processor for a readout device that reads outdata from a first recording medium having recorded therein data ofarbitrary plural portions of a period of a predetermined length intemporally continuous content, and data from a second recording mediumhaving recorded therein data of the entire content to executeprocessing, the program comprising: controlling, when the readout ofdata of the content is requested, the readout of data from the firstrecording medium such that data of any one of the portions recorded inthe first recording medium is read out; and controlling the readout ofdata from the second recording medium such that data following the dataread out from the first recording medium is read out from the secondrecording medium.
 11. A program recording medium in which a programaccording to claim 10 is recorded.
 12. A readout device, comprising: afirst recording medium having recorded therein data of arbitrary pluralportions of a period of a predetermined length in temporally continuouscontent; a second recording medium having recorded therein data of theentire content; and a readout control configured to control, when thereadout of data of the content is requested, the readout of data fromthe first recording medium and from the second recording medium suchthat data of any one of the portions recorded in the first recordingmedium is read out and data following the data read out from the firstrecording medium is read out from the second recording medium.